Metabolomics is a science that systematically examines and integrates the dynamic interplay between multiple, small molecule biomarkers that are uniquely characteristic of complex biological functions in health and disease. Metabolomics thus provides an interesting platform to investigate the pathophysiology of complex physiological syndromes at a molecular level, which in turn may lead to breakthroughs in the understanding and treatment of metabolic based disorders and diseases.
Recently, metabolomics has been utilised in the investigation of the pathophysiology of inflammatory bowel disease (IBD) (Marchesi, J. R., Holmes, E., Khan, F., Kochhar, S., Scanlan, P., Shahahan, F., Wilson, I. D., Wang, Y., Rapid and noninvasive metabonomic characterization of inflammatory bowel disease, J Proteome Res, 2007, 6:546-51), obesity and cancer. Marchesi et al. characterized the fecal extracts of Crohn's disease (CD) and ulcerative colitis (UC) patients by reduced levels of short chain fatty acids such as butyrate and acetate, methylamine, and trimethylamine, suggesting obvious changes in the gut microbial community due to the inflammation.
Metabolomics, restricted to the investigation of lipids only, is called lipidomics and may be used to identify and clarify the mechanisms behind lipid based diseases. A lipidomic analysis has i.a. been used in the characterization of fatty liver of genetically obese insulin resistant mice (Yetukuri, L., Katajamaa, M., Medina-Gomez, G., Seppänen-Laakso, T., Vidal-Puig, A., Oresic, M., Bioinformatics strategies for lipidomics analysis: characterization of obesity related hepatic steatosis, BMC Systems Biol., 2007, 1:12).
There is increasing evidence indicating that several lipids, such as eicosanoids, diacylglycerols, lysophosphatidic acids, and sphingolipids, especially ceramides, are able to enhance pain perception. Many of these lipids are second messengers in signaling pathways that are associated with increasing the sensitivity of sensory neurons, whereas others are putative inflammatory mediators that activate either surface receptors or ion channels in these neurons. These provide optional targets for therapeutics to treat inflammation and chronic pain states (Park, K. A., Vasko, M. R. Lipid mediators of sensitivity in sensory neurons, trends in Pharmacological Science, 2005, 26(11):571-577).
Malan et al., have reviewed the contribution of lipid messengers in regulating specific physiological functions, the transmission of noxious sensory information (pain) in the nervous system. They found that lipid molecules play major roles in the modulation of pain sensitivity. Six types of lipid molecules (prostanoids, phosphatidyl inositol biphosphate, ceramide, lipoxygenase metabolites of arachidonic acid, fatty acyl dopamines, and acylethanolamides) have been shown to modulate systems important in the regulation of pain responses. Prostaglandin is a prostanoid of importance in pain, which is illustrated by the fact that non-steroidal anti-inflammatory drugs inhibiting the formation of prostaglandins are the most widely used drugs for alleviating pain. The effects of ceramide or C2-ceramide have been found to be inhibited by glutathione, an inhibitor of neutral sphingomyelinase that liberates ceramide from neutral sphingomyelins. A blocking antibody against a receptor mediating the release of ceramide has been found to inhibit the effects of a nerve growth factor (NGF) on cellular excitability and on delayed-rectifier potassium channels. (Malan, T. P., Porreca, F. Lipid mediators regulating pain sensitivity, Prostaglandins & other Lipid Mediators, 2005, 77:123-130).
It is thus generally acknowledged that metabolites, such as lipid metabolites, may have an impact on a number of diseases and disorders including pain perception. Still the identification of diseases associated with an abnormal metabolic profile and the understanding of the pathophysiology of such diseases are insufficient. Even less is known about the possibilities of implicating an abnormal metabolic profile in order to prevent or treat the disease. The present invention contributes to solving these issues.
Probiotic microorganisms are microorganisms known to have a health promoting effect. Many of the probiotics are bacteria, especially lactic acid bacteria. Yan et al. provide a molecular basis for a therapeutic application of probiotics for inflammation-mediated intestinal disorders. They purified two novel proteins p75 and p40 from Lactobacillus rhamnosus GG (LGG), which were demonstrated to promote intestinal epithelial homeostasis through specific signaling pathways. These findings suggest that probiotics may be useful for cytokine-mediated gastrointestinal diseases because they inhibited cytokine-induced epithelial cell apoptosis, and significantly reduced TNF-induced colon epithelial damage. (Yan, F., Cao, H., Cover, T. L., Whitehead, R., Washington, M. K., Polk, D. B., Soluble proteins produced by probiotic bacteria regulate intestinal epithelial cell survival and growth. Gastroenterology, 2007, 132(2):562-75).
Lam et al. showed that Lactobacillus rhamnosus GG (LGG) protects mucosal cells from apoptosis in the stomach. They found that LGG pretreatment significantly increased the basal mucosal prostaglandin E2 (PGE2) level, and proposed a protective action of LGG on gastric mucosal lesions due to the up-regulation of PGE2, which could stimulate the mucus secretion and increase the transmucosal resistance in the gastric mucosa (Lam, E. K., Tai, E. K., Koo, M. W., Wong, H. P., Wu, W. K., Yu, L., So, W. H., Woo, P. C., Cho, C. H., Enhancement of gastric mucosal integrity by Lactobacillus rhamnosus GG, Life Sci, 2007, 80(23):2128-36).
Furthermore, Schultz et al. showed the effect of oral administration of L. rhamnosus GG to healthy volunteers on the cytokine secretion profile. They demonstrated that the cytokine profile shifts towards an enhanced anti-inflammatory response by a heightened secretion of suppressive cytokines (IL-10, IL-4) and decreased secretion or pro-inflammatory cytokines (TNF-α, IL-6, IFN-γ) (Schultz, M., Linde, H. J., Lehn, N., Zimmermann, K., Grossmann, J., Falk, W., Schölmerich, J., Immunomodulatory consequences of oral administration of Lactobacillus rhamnosus strain GG in healthy volunteers, J Dairy Res, 2003, 70:165-173).
Still further, probiotic bacteria, such as lactobacilli, bifidobacteria and lactococci, have been suggested to alleviate symptoms of irritable bowel syndrome IBS (overall symptom score, flatulence, bloating). A review by Camilleri and Gorman concludes that there appears to be at least one IBS subgroup with increased gut permeability, although the role of permeability defects in IBS is not fully elucidated. Studies on modulators of intestinal permeability include probiotics, proteinase activated receptor (PAR), IFN-γ, and glutamine, but the data are considered too preliminary to draw any conclusions from. Furthermore, a raised number of inflammatory cells in mucosal biopsies and an abnormal interleukin (IL)-10/IL-12 ratio suggest the presence of slight/low-grade inflammation in some IBS patients (Camilleri, M., Gorman H., Intestinal permeability and irritable bowel syndrome, Neurogastroenterol Motil, 2007, 19: 545-52).
Still there is little knowledge about the actual mechanisms that regulate the beneficial effects of probiotic bacteria at the level of host cells of the whole organism. In a review by Verdu et al., a number of putative mechanisms are mentioned. Probiotics have been found to reduce the duration of infectious diarrhea in children, modulate the inflammatory response to infection by reducing an abnormal systemic ratio of interleukin 10 to interleukin 12 in patients with IBS, stabilize intestinal barrier function in children with atopic dermatitis, improve muscle function in post infection IBS, reduce abnormal fermentation in the gut, and possibly affect neurotransmission and modulate visceral perception in IBS. Conflicting results have been obtained regarding a decreasing effect of particular probiotics on pain. (Verdu, E. F., Collins, S. M., Irritable bowel syndrome and probiotics: from rationale to clinical use, Current Opinion in Gastroenterology, 2005, 21:697-701).
Kajander et al., found an alleviating effect of probiotics on IBS symptoms, and suggest that the underlying mechanisms induced by the probiotics may involve for instance anti-inflammatory effects, balancing of the microbiota or motility-related effects (Kajander, K., Hatakka, K., Poussa, T., Fräkkilä, M., Korpela, R., A probiotic mixture alleviates symptoms in irritable bowel syndrome patients: a controlled 6-month intervention, Aliment Pharmacol Ther., 2005, 22: 387-394; Kajander, K., Korpela, R., Clinical studies on alleviating the symptoms of irritable bowel syndrome with a probiotic combination, Asia Pac J Clin Nutr, 2006, 15(4):576-580).
WO 2007/36230 describes a ready-to-use product containing specific amounts of fermented cereal, non-pathogenic microorganisms, and optionally phospholipids, preferably phosphaditylcholine, for treating inflammatory gastrointestinal diseases, e.g. inflammatory bowel disease (IBD) and inflammatory bowel syndrome (IBS). Such a composition is said to considerably improve probiotic treatments of IBD, IBS and other gastrointestinal disorders.
The present invention now provides a novel indication of probiotics.